A typical SR motor includes multiple salient poles on both the stator and the rotor. Windings or coils are wound on the stator poles, and each pair of windings on diametrically opposite stator poles are connected in series or in parallel to form an electrically independent phase of the SR motor. The rotor is made of a magnetically permeable material such as, for example, a ferrous alloy. Electronics are utilized to energize the independent phases of the SR motor which thereby produce a magnetic field that interacts with the rotor poles to turn the rotor and the shaft to which the rotor is attached.
The simple design of SR motors is a feature which allows SR motors to generally last longer than other types of motors that are used in electrical devices. SR motors do not utilize permanent magnets, brushes and/or commutators as are typically used on the other types of motors. Elimination of these components reduces the maintenance needs and increases the life span of the SR motor when compared with the other types of motors.
SR motors also offer a number of other benefits over the other types of motors. These benefits include increased performance and a rugged construction for harsh environments. SR motors generally produce more torque than similarly sized models of the other types of motors. SR motors include efficiencies that are consistent over a wider range of operation and that are at least as good as the other types of motors. SR motors also include high speed and high acceleration capabilities. The benefits of SR motors make the use of SR motors desirable in a wide variety of electrical devices.